The SI/MO team of Cnes Toulouse is in charge of the development of Level 2 algorithms applied to VEGETATION P data in the frame of CYCLOPES project. To get surface reflectance, the methodology consists in :
  removing clouds and their shadows, using thresholds depending on the classes of the GLC2000 land cover map
  correcting the scattering and absorption effects due to atmosphere and aerosols.

In a second step, these daily reflectances are normalized following the approach defined by the MATIS team of CNRM/Météo-France. The semi-empirical linear model of Roujean et al. (1992) is inverted to correct the directional effects due to changes in angular configuration during the synthesis period. Successives inversions and thresholds on model fitting allow to remove observations disturbed by residual clouds and/or aerosols, following the method presented by Hagolle et al.(2004). The last inversion, giving the directional coefficients of the Bidirectional Reflectance Distribution Function (BRDF), is performed applying a gaussian temporal weighting function putting the maximum weigth on observations acquired during the central 10-day period of the synthesis. Inversions are carried out over synthesis period of 31 days, centered on 5th, 15th, and 25th of each month. The normalized surface reflectance is finally calculated for a nadir viewing angle and the solar angle at 10:00 local time.

The normalized surface reflectances (1999 - 2003) are included in the product "Reflectance". The version 3 is available on request, with a readme file. They are provided in tiles of 10°x10° covering the whole globe in plate-carrée projection. The map locating the tiles can be downloaded.
Surface reflectances have been extracted over 323 sites of the BELMANIP database (Baret et al., 2006) used for validation. These extractions covering areas about 50km*50km can be downloaded, with a list and description of sites.